The lead wire coating and coil insulator used in solenoid valves, etc. deteriorate over long usage or due to the influence of ambient temperature. In order to use our valves safely, insulation class is noted in the specifications according to the insulation material used. Products in each insulation class (heat resistance class) cannot be used over the temperature shown in Table 1 (Reference: JIS C 4003). Please use our solenoid valves within a limit such that the temperature of coil temperature increase (°C) plus ambient temperature (°C) does not exceed the temperature of insulation class (heat resistance class). For related information, please refer to Resistance Method or Duty Cycle (ED) in the Glossary in this website as well.